The same kind of methods can be applied to internet websites, even more easily because it's digital. GDPR doesn't say anywhere that you can't do analytics or whatever on your website, it only says that you can't track the user, but there are plenty of way to do analytics in a GDPR compliant way, and there are a number of even open source projects alternative to Google Analytics for example that allows to do so.
Of course what you can no longer do (without user consent, because if the user give you explicit consent you can) is to provide ADS targeted to a specific user based on tracking data. But you can assume that if a user visits a page that has a certain content it will be interested in certain type of ads, this is possible because you are not targeting the specific user based on data you collected on the user, but all the user that look at that content will see the same ads (that are pertinent).
Is a big loss? Yes, to Meta and Google, to company doing advertisement not, because this kind of advertisement is not that effective, and to users even more not because tracking is bad for their privacy in many ways.